1. Field of the Invention
The present invention relates to a vehicular fluid sealed engine mount which is used to mount an engine on a body of a vehicle.
2. Description of the Background Art
Engines of vehicles generate various types of vibrations which differ largely in frequency and amplitude according to engine revolution speeds. In recent years, there have been in progress developments of vehicular fluid sealed engine mounts which can absorb a wide range of vibrations generated by engines (for example, refer to Patent Document No. 1).
[Patent Document No. 1]
JP-A-2001-193783
These general vehicular fluid sealed engine mounts are such that a first mount member adapted to be mounted on a power source and a second mount member which is cylindrical and is adapted to be mounted on a body are connected to each other via a resilient member such as a rubber, a fluid chamber is provided by a diaphragm mounted on the second mount member and the resilient member, the fluid chamber so provided is partitioned by a partition member into a main fluid chamber and an auxiliary fluid chamber, and the main fluid chamber and the auxiliary fluid chamber are made to communicate with each other via two orifices.
When the engine revolves in a high engine revolution speed area, a working fluid is allowed to pass between the main fluid chamber and the auxiliary fluid chamber only via one of the orifices so as to damp the vibrations of the engine. In addition, when the engine revolves in a low engine revolution speed area (idling speed area), the working fluid is allowed to pass between the main fluid chamber and the auxiliary fluid chamber via the two orifices so as to damp the vibrations of the engine.
Incidentally, when the vehicle is involved in a collision, impact energy is also applied to the engine mount which is interposed between the body, which is deformed by virtue of the impact energy applied thereto, and the engine. Since the fluid sealed engine mount has a larger number of components accommodated in the interior thereof, the fluid sealed engine mount may sometime function as a rigid body rather than an impact absorbing member. Consequently, it has been desired that fluid sealed engine mounts also have an improved energy absorbing performance.